Windsurf (formerly Codeium) is Codeium's agentic IDE that combines a VS Code-based code editor with an AI system called Cascade that understands entire codebases and executes complex multi-file engineering tasks autonomously. Unlike standard AI code assistants that suggest single completions, Cascade can plan and implement entire features, debug across files, refactor large codebases, and run terminal commands — functioning as a true AI engineering partner. Developers use Windsurf when they need an AI that can handle the full scope of a real engineering task, not just autocomplete.